1. Field of the Invention
This invention relates to a new and useful improvement in synthesizing crystalline silicate having the structure of ZSM-5, the new ZSM-5 synthesized, and to use of the crystalline silicate synthesized in accordance herewith as a catalyst component for organic compound, e.g. hydrocarbon compound, conversion.
More particularly, this invention relates to an improved method of preparing crystalline silicate ZSM-5 whereby synthesis is facilitated and reproducible and the silicate product exhibits high purity and catalytic utility.
2. Discussion of Prior Art
Crystalline silicate ZSM-5 and its conventional preparation are taught by U.S. Pat. No. 3,702,886, the entire disclosure of which is incorporated herein by reference. It has a distinctive X-ray diffraction pattern which identifies it from other known crystalline silicates. A crystalline silicate composition having the structure of ZSM-5 is taught in U.S. Pat. No. Re. 29,948, the entire disclosure of which is incorporated herein by reference.
U.S. Pat. No. 4,139,600 teaches a method for synthesis of zeolite ZSM-5 from a reaction mixture comprising, as a directing agent, an alkyldiamine. U.S. Pat. No. 4,296,083 claims synthesizing zeolites characterized by a constraint index of 1 to 12 and an alumina/silica mole ratio of not greater than 0.083 from a specified reaction mixture containing an organic nitrogen-containing cation provided by an amine identified as being selected from the group consisting of triethylamine, trimethylamine, tripropylamine, ethylenediamine, propanediamine, butanediamine, pentanediamine, hexanediamine, methylamine, ethylamine, propylamine, butylamine, dimethylamine, diethylamine, dipropylamine, benzylamine, aniline, pyridine, piperidine and pyrrolidine.
U.S. Pat. No. 4,151,189 claims a method for synthesizing zeolites ZSM-5, ZSM-12, ZSM-35 and ZSM-38 containing an organic nitrogen cation from a specified reaction mixture containing a primary amine having 2 to 9 carbon atoms as a directing agent. U.S. Pat. No. 4,341,748 shows synthesis of ZSM-5 structure from reaction mixtures comprising ethanol, ZSM-5 seeds, ethanol and seeds, ethanol and ammonimum hydroxide, and ethanol, ammonimum hydroxide and ZSM-5 seeds. U.S. Pat. No. 4,100,262 teaches synthesis of ZSM-5 from a reaction mixture comprising a tetraalkylammonium source and a tetraureacobalt (II) complex.
Applicant knows of no prior art for preparing crystalline silicate ZSM-5 utilizing as a directing agent an anionic compound such as an organosulfonic acid as required of the present invention.